1. Field of the Invention
This invention relates to a hydraulic puncher suitably used for punching holes in a C-shaped shape steel member.
2. Description of the Related Art
As shown in FIG. 3, the conventional hydraulic puncher 50 for punching holes in a C-shaped shape steel member has a die mount 53 fixed to the upper surface of the front end of the lower frame 51 of a puncher body 2. The die mount 53 has such a width as is allowed to pass through an opening 23 defined between tongue portions 24 formed on both lower lateral side ends of the flat portion 22 of a workpiece 21. When the die mount 53 is removed, the front portion of the lower frame 51 exhibits a large opening 58. Since the workpiece 21 has arm portions 25 extending by a length M between the flat portion 22 and the tongue portions 24, the die mount 53 on which a die 55 is mounted must be fixed to the upper surface of the front end of the lower frame 51 upon using the hydraulic puncher 50.
On the conventional hydraulic puncher 50, therefore, holes can be punch-formed in the central portion of the workpiece 21 which is placed on the upper surface of the die 55 by moving the die mount 53 along the workpiece 21 in its opening 23. Because the tongue portions 24 which are formed parallel with the flat portion 22 and project inwardly, the forward ends of the tongue portions 24 abut against the lateral sides of the die mount 53 when the workpiece 21 is moved rightward or leftward in FIG. 3. Thus, the lateral sides 25 of the workpiece 21 cannot approach the die mount 53 beyond a predetermined distance. Therefore, the conventional hydraulic puncher 50 has a problem that holes cannot be formed in those portions of the flat portion 22 of a workpiece which are close to its arms 25.
This invention was made to overcome the problem of the conventional hydraulic puncher, and the object thereof is to provide a hydraulic puncher in which an escaping groove for receiving one of the tongue portions of a workpiece so as to increase the rightward and leftward movement of a workpiece like a C-shaped shape steel member is formed in that lateral side of a die mount fixed to the upper surface of the front end of the lower frame of the hydraulic puncher which is at the side of the lower frame, such that holes are punch-formed in any parts of the flat portion of the workpiece.
This invention provides a hydraulic puncher which comprises a generally C-shaped frame member having a pair of opposed ends, a connecting portion for connecting the opposed ends together, and an opening defined between the opposed ends, for receiving a part of a workpiece, a hydraulically driving mechanism connected to one of the opposed ends of the frame member, a ram provided on the front end thereof with a punch and driven by the driving mechanism, a die supported by the other end of the frame member and cooperating with the punch, and a die mount removably mounted on the other end of the frame member for fixedly holding the die, the die mount being provided in a side thereof opening toward the connecting portion with a groove for being capable of receiving a part of the workpiece.
Since an escaping groove for receiving a tongue of a workpiece like a C-shaped shape steel member is formed in that side of the die mount fixed to the upper surface of the front end of the lower frame which is at the side of the lower frame, each lateral side of the workpiece is made to approach the die mount much more than in the case of the conventional hydraulic puncher by moving the workpiece back and forth with respect to the lower frame, whereby holes can be punch-formed in the portions of the flat portion of the workpiece which are close to the right and left sides of the workpiece. According to this invention, therefore, a variety of holes can be formed in a workpiece with much improved punching operation.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.